1. Field of the Invention
This invention relates to a manually operable apparatus for processing individual rolls of photographically exposed film.
2. Description of the Prior Art
The present invention relates to a manually operable, compact, portable processor which is adapted to be used in the processing of individual rolls of photographic film, preferably of the 35 mm self-developing or instant type transparency film and, more particularly, to such a processor which includes an interlock for insuring the proper sequence of events during a processing cycle.
Often, apparatus of the type described have a processing cycle wherein events must be carried out in a predetermined sequence. For example, in a processor of the type described and shown in U.S. Pat. No. 4,445,770, a rack is mounted for linear movement between a first position, wherein the processor's loading door may be opened, to a second position. As the rack is moved toward the second position, by virtue of the manual rotation of a lever, it opens a processing kit and locks the cover or loading door in its closed position thereby rendering the housing lighttight during the processing of a roll of film. However, if the rack were initially located in the second position at the time that the processing kit was inserted into the processor, an arm of the rack would not be located correctly relative to a movable housing section of the processing kit. Thus, it is possible that when the loading door is moved into its closed position, a lip on the loading door may be cammed outwardly by an arm and thence sprung inwardly under a latching surface thereby locking the loading door in the closed position. Note, although the arm extends outwardly into the path of movement of the door because the rack is in the second position, it, the arm does not prevent the door from being closed. Next, counterclockwise rotation of the lever by the operator into a vertical position will result in the connection between the lever and a sector gear being broken, generally without the operator's knowledge. The operator then will rotate a crank to thereby withdraw the exposed film from its film cassette and a length of sheet material from the kit while simultaneously winding them in superposition upon a take-up roller. Ordinarily, the sheet material would have a coating of processing liquid thereon but, since the lever connection with the sector gear was broken, the lever was never able to move a rupturing member into rupturable engagement with a container of processing liquid located within the processing kit. Even if it could move the rupturing member, the processing kit is still closed and thus more breakage would possibly occur. The final steps in the processing cycle are then attempted by the operator, i.e., (1) the lever is returned to its original position after a sixty second wait for the film to be developed (which has not been done), (2) the crank is again rotated in an attempt to rewind the film and sheet material into their original containers (which does not happen because movement of the lever in step 1 failed to return the rack to the first position), and (3) an attempt is made to open the loading door (which is still latched in the closed position). Finally, when the operator is able to pry the loading door open, thus possibly causing more damage to the processor, the exposed film (which is still on the take-up roller) is then fogged by the ambient light because it is still in an undeveloped condition. Accordingly, it can readily be appreciated that there is a need to construct such a film processor in a way which will insure that the different steps in the processing cycle are carried out in a predetermined sequence. One way of accomplishing such a construction may be by way of an interlock, as was done in U.S. Pat. No. 4,417,799.